This invention relates to the manifold imaging process and more particularly to a novel thermally activated imaging member and method.
There has been discovered an imaging technique generally referred to as the manifold imaging method wherein an imaging member comprising a donor layer, imaging layer and receiver layer is employed. The imaging layer is electrically photosensitive and in one form comprises an electrically photosensitive material such as metal-free phthalocyanine dispersed in an insulating binder. Typically, the imaging layer is coated on the donor layer and the coated substrate combined is termed a donor. When needed, in preparation for the imaging operation, the imaging layer is activated as by contacting it with a swelling agent, softening agent, solvent or partial solvent for the imaging layer. The imaging layer is typically exposed to an imagewise pattern of light to which it is sensitive and, while sandwiched between the donor and receiver layers, subjected to an electric field. The imaging layer fractures upon the separation of the donor and receiver layers while subjected to an electric field providing complementary positive and negative images on the donor and receiver layers in accordance with the image to which it was exposed.
Such manifold imaging method is more fully disclosed in U.S. Pat. No. 3,707,368 to Van Dorn which patent is hereby incorporated by reference. As is taught in said patent the imaging layer is typically activated by applying thereto an activator material. Subsequent efforts in the manifold imaging science has produced other methods of activation such as thermo-activation as disclosed in U.S. Pat. No. 3,598,581 to Reinis which patent is hereby incorporated by reference. Although activation as disclosed by Reinis eliminates the need for handling liquid activators at the imaging site, such process provides a wax component on the final image and a carryover in image background areas. In addition, the Reinis imaging member contains a separate layer of thermo-activator over the imaging layer. Thus, an additional coating step is needed requiring great care so as not to damage the imaging layer in those instances wherein the thermo-activator is not coated on the receiver layer. Images produced by such processes contain the thermo-activator on the image and background areas. There is desired a thermo-activator method which reduces the amount of wax on the image and background areas.
The result of other work related to thermo-activation of a manifold imaging layer is described in copending U.S. application Ser. No. 210,658 filed Dec. 22, 1971. The problem of wax carry-over in image background areas is reduced according to said copending application by placing the hot melt coated thermo-activator layer under the imaging layer rather than over it as disclosed in the Reinis patent. While such method reduces the amount of activator carry-over in background areas on the receiver there has been found several narrow process parameters such as coating thickness and activator temperature for optimum image quality. Again, an additional coating step is necessary to provide the separate layer of thermo-activator in the imaging member.